CN113691059A

CN113691059A - Dynamic pressure air bearing improved structure for reducing rotor whirling

Info

Publication number: CN113691059A
Application number: CN202110862291.5A
Authority: CN
Inventors: 张俊; 赵小明; 白永杰; 刘志宏; 武丽花
Original assignee: 707th Research Institute of CSIC
Current assignee: 707th Research Institute of CSIC
Priority date: 2021-07-29
Filing date: 2021-07-29
Publication date: 2021-11-23
Anticipated expiration: 2041-07-29
Also published as: CN113691059B

Abstract

The invention relates to an improved structure of a dynamic pressure air bearing for reducing rotor whirling, which comprises a shaft, a rotor assembly, two thrust plates positioned on the left side and the right side, and locking nuts positioned on the left side and the right side; the rotor assembly is sleeved outside the shaft, and a radial fit clearance is formed between the inner circular hole surface of the rotor assembly and the outer circumferential surface of the shaft; the two thrust plates are respectively and tightly leaned against shoulders at the left end and the right end of the shaft through two locking nuts, and end face fit clearances are respectively formed between the inner end faces of the two thrust plates and the left end face and the right end face of the rotor assembly; the center of the shaft is provided with an axial vent hole, the radial direction of the shaft is provided with a radial vent hole, and the radial vent hole enables the axial vent hole to be communicated with the radial fit clearance. The improved structure reduces the whirling of the rotor and improves the rotating speed stability of the rotor, thereby improving the drift precision of the gyroscope.

Description

Dynamic pressure air bearing improved structure for reducing rotor whirling

Technical Field

The invention belongs to the technical field of dynamic pressure bearing gyro motors, and particularly relates to an improved structure of a dynamic pressure air bearing for reducing rotor whirling.

Background

In a liquid-level gyroscope, a motor is one of the very critical components, and the normal operation of the motor is a necessary condition for generating the gyroscopic effect. The motors for the high-precision long-life liquid floating gyroscope all adopt dynamic pressure air bearing.

In practical application, factors such as dynamic pressure air bearing performance of the gyro motor, mass unbalance of the rotor, assembly errors, thermal deformation and centrifugal deformation of the motor in the operation process can cause the rotor to perform vortex operation, so that the rotation speed stability of the gyro motor is influenced, interference torque is generated, and the drift precision of the gyroscope is further influenced.

Among them, the dynamic pressure gas bearing plays a major role in performance. The structure of the dynamic pressure air bearing of the prior gyro motor is shown in fig. 2, and mainly comprises a thrust plate 2 (a left thrust plate and a right thrust plate), a shaft 9, a rotor assembly 4 and a locking nut 1, and further comprises a stator assembly 3 which plays a role in floating and limiting the rotor assembly. An end face fit clearance 6 is arranged between the thrust plate and the end face of the rotor assembly, the thrust plate and the rotor assembly form a thrust bearing of the dynamic pressure gas bearing, a radial fit clearance 5 is arranged between the outer cylindrical face of the shaft and the hole of the rotor assembly, and the thrust plate and the rotor assembly form a radial bearing of the dynamic pressure gas bearing.

The direction of gas flow in the air bearing is shown by the arrows in FIG. 2. External air respectively enters from a thrust bearing inlet (A, B) and flows along the arrow direction, and the two air streams meet at the middle part of the radial bearing and collide to generate turbulence, so that the performance of the bearing is reduced, the whirling of a rotor is caused, and the drift precision of the gyroscope is reduced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the improved structure of the dynamic pressure air bearing, which can reduce the whirling of the rotor, improve the rotating speed stability of the rotor and further improve the drift precision of the gyroscope.

The above object of the present invention is achieved by the following technical solutions:

an improved structure of a dynamic pressure air bearing for reducing rotor whirling comprises a shaft, a rotor assembly, two thrust plates positioned on the left side and the right side, and locking nuts positioned on the left side and the right side; the rotor assembly is sleeved outside the shaft, and a radial fit clearance is formed between the inner circular hole surface of the rotor assembly and the outer circumferential surface of the shaft; the two thrust plates are respectively and tightly leaned against shoulders at the left end and the right end of the shaft through two locking nuts, and end face fit clearances are formed between the inner end faces of the two thrust plates and the left end face and the right end face of the rotor assembly respectively; the method is characterized in that:

the center of the shaft is provided with an axial vent hole, the radial direction of the shaft is provided with a radial vent hole, and the radial vent hole enables the axial vent hole to be communicated with the radial fit clearance.

Further: the diameter of the radial vent hole is phi 1 mm-phi 1.5 mm.

The invention has the advantages and positive effects that:

on the basis of the original gyro motor, the axial vent hole is additionally arranged at the center of the shaft, and the radial vent hole communicated with the axial vent hole and the radial fit clearance is additionally arranged on the shaft, so that part of gas in two gas flows entering the radial fit clearance flows into the radial vent hole firstly, then flows into the axial vent hole, is discharged from two ends of the axial vent hole and flows back to the running environment of the motor. The scheme reduces the collision of two gas streams, thereby reducing the whirling of the rotor, improving the stability of the rotating speed of the rotor and further improving the drift precision of the high gyroscope.

Drawings

FIG. 1 is a schematic view of a modified dynamic pressure gas bearing structure according to the present invention;

fig. 2 is a schematic structural view of a conventional hydrodynamic gas bearing.

Detailed Description

The structure of the present invention will be further described by way of examples with reference to the accompanying drawings. It is to be understood that this embodiment is illustrative and not restrictive.

An improved structure of dynamic pressure air bearing for reducing rotor whirling motion is disclosed, please refer to fig. 1, which comprises a shaft 9, a rotor assembly 4, two thrust plates 2 located at left and right sides, and lock nuts 1 located at left and right sides. The rotor assembly is sleeved outside the shaft, and a radial fit clearance 5 is formed between the inner circular hole surface of the rotor assembly and the outer circular surface of the shaft. The two thrust plates are respectively and tightly leaned on shoulders at the left end and the right end of the shaft through two locking nuts, and end face fit gaps 6 are formed between the inner end faces of the two thrust plates and the left end face and the right end face of the rotor assembly respectively. The invention is characterized in that:

the center of the shaft is provided with an axial vent hole 8, the radial direction of the shaft is provided with a radial vent hole 7, the radial vent hole enables the axial vent hole to be communicated with the radial fit clearance, the number of the radial vent holes can be 1 or more, and under the condition of adopting the design structure of a plurality of radial vent holes, the plurality of radial vent holes adopt the structure uniformly distributed and designed along the circumferential direction. The diameter of the radial vent hole is phi 1 mm-phi 1.5 mm.

In addition to the above technical features related to the present invention, the size of the radial fit clearance, the size of the end face fit clearance, the composition of the rotor assembly, the composition of the stator assembly 3 in the dynamic pressure air bearing, the fit relationship between the rotor assembly and the stator assembly, the design of the air guide spiral groove on the inner end faces of the two thrust plates, the design of the air guide spiral groove on the outer circular surface of the shaft, and the like refer to the prior art, and are not described herein again.

The airflow direction of the improved structure of the dynamic pressure air bearing is shown in figure 1, specifically:

the direction of gas flow in the air bearing is shown by the arrows in FIG. 1. External air respectively enters from an inlet (A, B) of the thrust bearing and flows along the arrow direction, two air streams meet at the middle part of the radial bearing, wherein part of the air flows into the radial vent holes firstly, then flows into the axial vent holes, is discharged from two ends of the axial vent holes and flows back to the running environment of the motor, and airflow circulation is formed. The flow circulation of the air flow is completed inside the gyro float.

The following embodiments further illustrate the technical effects of the improved structure of the pneumatic floating bearing.

Results of control group experiments:

the number of the motors of a certain model is six, and the motors are averagely divided into two groups. Wherein, the shaft of the group A motor is provided with an axial vent hole and a radial vent hole, as shown in figure 1; the shaft of the group B motor does not have any holes, as shown in fig. 2. The other parts of the two sets of motors are identical.

Theoretical calculation and practical experience show that when the motor works, the rotating speed stability (rotating speed variable quantity/rated rotating speed) of the motor is linearly related to the precision of the gyroscope, namely the higher the rotating speed stability of the motor is, the higher the precision of the gyroscope is.

The rotational speed stability of the two groups of motors in a helium gas medium under the conditions of normal temperature and normal pressure and 30000RPM of the motor is measured, and is shown in the following table.

TABLE 1 comparison chart of rotational speed stability of two sets of motors

As can be seen from table 1: the rotating speed stability of the motor (A group) with the improved structure is greatly superior to that of the motor with the existing structure.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit of the invention and the scope of the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.

Claims

1. An improved structure of a dynamic pressure air bearing for reducing rotor whirling comprises a shaft, a rotor assembly, two thrust plates positioned on the left side and the right side, and locking nuts positioned on the left side and the right side; the rotor assembly is sleeved outside the shaft, and a radial fit clearance is formed between the inner circular hole surface of the rotor assembly and the outer circumferential surface of the shaft; the two thrust plates are respectively and tightly leaned against shoulders at the left end and the right end of the shaft through two locking nuts, and end face fit clearances are formed between the inner end faces of the two thrust plates and the left end face and the right end face of the rotor assembly respectively; the method is characterized in that:

2. The dynamic pressure gas bearing improvement structure for reducing rotor whirl according to claim 1, wherein: the diameter of the radial vent hole is phi 1 mm-phi 1.5 mm.